植物石蜡制片中透明和脱蜡技术的改良

石蜡切片是植物科学研究领域中一项重要的实验技术,为组织学的发展做出了卓越贡献。制片过程中采用不同试剂和处理程序对切片质量有较大的影响。该文针对常规石蜡切片方法在操作步骤上存在的繁琐及试剂安全性等问题,摸索出改进方法。实验结果表明,采用histolene(C1OH16)、环保透明剂van-clear、正丁醇(n-butanol)和松节油(oil of turpentine)代替二甲苯(xylene),可避免二甲苯的毒性危害;同时精简了传统石蜡切片的操作程序,缩短了实验周期并提高了制片质量。     

常规石蜡切片方法的改良

针对传统石蜡切片方法中的缺陷,对制片方法进行了相应的改良。总结了切片制作过程中可能存在的问题以及处理对策;提出了一些能缩短实验周期,解决实验有毒物质二甲苯污染的方案。结合教学实践发现改良方案有助于提高石蜡切片的质量。     

关于改革石蜡切片工艺的试验

众所周知,在石蜡切片的制作过程中,历来是用苯类(尤其是二甲苯)作为透明剂和石蜡的有机溶剂。组织块经酒精脱水后,必须再用二甲苯作为中间媒剂将酒精取代出来,然后才能进行透蜡。否则,虽然水分除尽,但组织内部积蓄酒精,石蜡仍难透入。同样,切片染色前和染色后,也需用二甲苯脱蜡和透明。因此,在整个制片过程中,不但要多次用到二甲苯,手续繁琐,而且组织块在二甲苯中浸渍时间较难掌握,久浸会使材料松脆,影响切片质量;时间不足又会影响透蜡效果。另外,苯类是有毒药品,且有致癌作用,对人体极为有害,国外组织学实验室     

植物材料快速石蜡制片方法

真空干燥箱已越来越广泛地应用于现代生物学研究领域。该文利用真空干燥箱温度和负压的可控制性能,将固定、脱水、透明和石蜡渗透等过程在真空干燥箱中进行,建立起一套可行的植物组织快速石蜡制片方法。结果显示,真空干燥箱的应用加速了多种试剂的渗透速率,提高了切片质量,达到了优化实验步骤、节省实验时间和减少室内有毒化学气体污染的目的。     

病理石蜡制片中试剂标准化操作的应用体会

近年来,随着经济的发展,蜡块制作由人工操作转向全自动密闭式脱水机的广泛使用,组织的固定、脱水、透明、浸蜡已进入恒温、恒湿化操作,有效地提高和稳定了病理制片的质量,但在各实验室石蜡HE制片中的试剂使用尚未统一实现标准化操作,影响了制作的蜡块质量稳定性。现将石蜡切片试剂标准化使用问题作如下探讨：     

超声快速石蜡病理切片免疫组织化学染色的分析讨论

超声快速石蜡病理制片方法简便快捷,切片质量好,组织染色清晰,与常规制片无明显差别,是目前国内手术中快速制片常用方法之一。手术中快速病理检查常常因为肿瘤组织较小而全部做成快速石蜡切片,在临床没有后续标本送检的情况下,使得赖以诊断的免疫组织化学就必须在快速石蜡切片上进行。因此,超声快速石蜡切片对免疫组化染色的影响是一个值得探讨的问题。     

木本植物非均质化组织石蜡切片制作方法

在常规石蜡切片技术的基础上, 针对木本植物茎段木质化程度高、硬度大以及各部分组织硬度不均匀等特点, 选取核桃(Juglans regia)茎段以及芽接愈合区域组织为实验材料, 对固定、软化和脱水等关键步骤进行改进, 获得结构完整且染色清晰的茎段组织和嫁接愈合区域组织切片, 可清晰地观察到各部分组织的形态特征和愈合过程中的发育特征, 且缩短了制片周期。采用改良后的实验流程成功获得了苹果(Malus pumila)、桃(Amygdalus persica)、杏(Armeniaca vulgaris)、李(Prunus salicina)和杨(Populus tomentosa)的茎段横截面切片。该方法为从解剖学上研究林木茎段生长机制和形态发育变化提供技术基础, 为非均质化植物材料的石蜡切片制作提供参考。     

FISH检测宫颈脱落细胞与宫颈组织中hTERC基因制片方法的研究

目的:探讨FISH实验中用直接涂片法、盐水制片法、TCT制片法、低渗滴片法制片法和宫颈切片组织取材方法对于FISH成功率的影响.方法:收集2008年3月至2009年3月青岛大学医学院附属医院妇科162例宫颈脱落细胞标本及2008年5月至2009年3月手术切除或活检的宫颈组织63例,用荧光原位杂交(FISH)方法检测hTERC基因.结果:直接涂片法、盐水制片法、生理盐水法、TCT制片法和石蜡包埋组织切片法hTERC基因杂交成功率分别为58.3%,65%,55%,87.1%,85.7%,TCT制片高于其它四组;低渗滴片法背景干净度、细胞形态、裸核数量满意度最高;TCT制片法细胞数量满意率最高;石蜡包埋组织切片法荧光信号满意率最高.结论:在检测hTERC基因的宫颈癌筛查中,TCT制片法明显优于其他方法,而在指导宫颈病变及宫颈癌的治疗中,石蜡包埋组织切片法的染色体破坏最小,实际意义更大.     

兔卵巢组织石蜡切片技术的改良

针对常规石蜡切片方法步骤繁多,耗时长,所用的二甲苯试剂对人体健康有较大毒害性的缺陷,探讨提高制作兔卵巢组织石蜡切片质量的方法。试验从脱水和透明环节进行技术改良,用正丁醇与无水乙醇混合剂取代常规的脱水剂和透明剂。该混合剂具有良好的脱水和透明作用。实验结果表明：通过该技术改良,镜下观察组织结构清晰可辨、颜色鲜艳、对比度好、层次分明,组织切片效果良好。试验改良技术的工艺简单,具有质优、省时、快捷和实用性较好等优点,有推广应用价值。     

观察比较贝母类生物碱分布的3种切片方法

目的:建立一种能更清楚有效地观察贝母鳞茎中生物碱沉淀分布及含量的切片方法。方法:以新疆贝母为供试材料,利用石蜡切片法、徒手切片法及改良切片法制备植物鳞茎组织切片;切片经改良碘化铋钾处理,并通过Mikroskop Primo Star X2005显微镜观察和比较3种不同切片中生物碱沉淀分布。结果:改良切片法处理的切片中生物碱沉淀分布观察清晰,可用于定性及定量分析,并且实验过程中试剂对生物碱的影响较小,操作方法简便、快速、有效。结论:贝母鳞茎生物碱的观测适合采用改良切片法制片。     

植物冰冻切片条件的优化及其与石蜡切片在组织化学应用中的比较

冰冻切片是植物组织学研究中一项重要的实验技术,冷冻温度和冷冻时间是决定切片质量的关键因素。通过比较15种冰冻切片条件,得出植物组织直接冰冻切片较适宜的冷箱温度、冷台温度和冷冻时间。同时,通过对5种植物的不同组织进行组织化学染色,比较了新鲜材料直接冰冻切片与常规石蜡切片在不同化学成分鉴定上的异同及各自的适用范围。结果表明,对于多糖、蛋白质和角质,两种切片方法的鉴定结果比较一致,但对于脂肪只能采用冰冻切片技术。研究结果对植物组织学实验和研究方法的改进具有一定的参考价值。     

Observation on Flower Bud Differentiation of Crape Myrtle in Red Soil Environment

Flower bud differentiation is a key component of plant blooming biology and understanding how it works is vital for flowering regulation and plant genetic breeding, increasing the number and quality of flowering. Red soil is the most widely covered soil type in the world, and it is also the most suitable soil type for crape myrtle planting. The flower buds of crape myrtle (Lagerstroemia indica) planted in red soil were employed as experimental materials in this study, and the distinct periods of differentiation were identified using stereomicroscopy and paraffin sectioning. We optimized the steps of dehydration, transparency, embedding, sectioning and staining when employing paraffin sections. When seen under a microscope, this optimization can make the cell structure of paraffin sections obvious, the tissue structure complete, and the staining clear and natural. The flower bud differentiation process is divided into 7 periods based on anatomical observations of the external morphology and internal structure during flower bud differentiation: undifferentiated period, start of differentiation period, inflorescence differentiation period, calyx differentiation period, petal differentiation period, stamen differentiation period, and pistil differentiation period. The differentiation time is concentrated from the end of May to mid-June. Crape myrtle flower bud differentiation is a complicated process, and the specific regulatory mechanism and affecting elements need to be investigated further.     

The Use of Ethylenediamine in Softening Hard Plant Structures for Paraffin Sectioning

Ethylenediamine has been used as an agent for softening very hard woods prior to sectioning on a sliding microtome. The use of ethylenediamine is recommended for two additional uses: for preparing 1) soft woods in which wide, thin-walled tracheids or vessels tend to collapse during sliding microtome sectioning and 2) plant tissues with sclerenchyma mixed with soft-walled cells (bark, leaves, fruits, etc.) which frequently fail to section well. After softening in ethylenediamine, material is washed, infiltrated, and embedded in paraffin. Preliminary sections are made with a rotary microtome, just exposing the cut surface of the material; this exposed surface is soaked overnight in water. Sectioning is then continued. Sections produced in this fashion are considerably improved. The wood and pith of Podocarpus ustus, a parasitic conifer from New Caledonia, is used as an object to demonstrate improvements in sectioning by the ethylenediamine-paraffin method. Thinner sections with minimal tearing, cell collapse, and unevenness are produced. Sections can be handled easily and stained more effectively than unmounted sections. Variations in timing and in treatment are recommended to suit different materials. Ethylenediamine, used with reasonable caution, is much less hazardous than hydrofluoric acid and is more effective in softening plant material. The ethylenediamine method may be used routinely on any material difficult to section because of hardness.     

An improved colloidal iron stain for glomerular sialoproteins

Summary The thick sialoglycoprotein coat of the glomerular epithelial cells is a part of the glomerular filtration barrier. It can be demonstrated in paraffin histology by means of the colloidal iron procedure. We have studied the special requirements of tissue processing to obtain reproducible results by this staining method. The requirements include proper fixation, avoiding heat during sectioning and ample rehydration. We have further tested a colloidal iron-PAS procedure for simultaneous demonstration of the glomerular epithelial coat and the basement membrane.     

Tape transfer sectioning of tissue microarrays introduces nonspecific immunohistochemical staining artifacts

Abstract

Tissue microarrays place tens to hundreds of formalin fixed, paraffin embedded tissue cores into a paraffin block in a systematic grid pattern that permits their simultaneous evaluation in a single section. The fragmented nature of the tissue cores often makes sectioning of tissue microarrays difficult so that the resulting disks of tissue lose their shape, fracture or fall out of the paraffin section altogether. We have evaluated an alternative sectioning protocol for stabilizing the tissue microarray surface by placing an adhesive tape “window” over the face of the paraffin block prior to sectioning. Once sectioned, the tape/sections are transferred directly onto coated microscope slides, thereby avoiding routine floating of sections on a water bath. After sectioning with either the tape transfer or standard protocols, slides were stained either using hematoxylin and eosin or immunohistochemistry using antibodies to S-100 protein and the tissue specific antigens, keratin (AE1/3) and the leukocyte common antigen CD45. We found that the tape method produced thicker sections that were darker and more densely packed with loss of tissue definition compared to sections prepared using water bath flotation. Quantitative image analysis of immunohistochemical staining demonstrated that the tape method produced a higher incidence of nonspecific staining, which raised the potential for false positive staining.     

A simplified paraffin embedding method for small botanical samples

Abstract

We present a simplified paraffin embedding method suitable for unsuberized or unlignified small botanical samples (diameter < 0.3 cm). Only 2 h are required to yield plant tissues embedded in paraffin for anatomical observation and molecular analysis. Our method achieved morphological preservation of cell structures and conservation of nucleic acids that were equivalent to the traditional protocol. Fourier transform infrared spectrometry showed that the degree of degradation of the cytoplasmic components (e.g., protein) resulting from our simplified protocol was similar to that of the traditional protocol. The DNA samples embedded using the simplified method was extractable and could be used for PCR analysis. The DNA quality was equivalent to that embedded using the traditional method.     

Block-Surface Staining

A method is described by which the tissue exposed on sectioning a specimen embedded in paraffin can be visualized in situ. The fixed specimen is impregnated with lead acetate, dehydrated in dioxane, infiltrated with paraffin and embedded. Tissues exposed on sectioning are developed by applying to the cut surface of the block a solution of potassium sulphide in water. Concentrations of the reagents used and the time intervals for the procedure are dependent upon the size of the specimen and upon the degree of contrast required. The method is described as it was applied to the study of a small human fetus in cross section. Representative photographs are included to show the results obtained.     

Fixation and decalcification of adult zebrafish for histological, immunocytochemical, and genotypic analysis

To facilitate the molecular analysis of tissues in adult zebrafish, we tested eight different fixation and decalcification conditions for the ability to yield DNA suitable for PCR and tissue immunoreactivity, following paraffin embedding and sectioning. Although all conditions resulted in good tissue histology and immunocytochemistry, only two conditions left the DNA intact as seen by PCR. The results indicate that zebrafish fixed in either 10% neutral buffered formalin or 4% paraformaldehyde, followed by decalcification in 0.5 M EDTA, is an easy and reliable method that allows molecular experiments and histology to be performed on the same specimen. The fixation and decalcification by Dietrich's solution permitted the PCR amplification of DNA fragments of 250 but not 1000 bp. Therefore, a protocol of formalin or paraformaldehyde fixation followed by decalcification with EDTA is broadly applicable to a variety of vertebrate tissues when excellent histological, immunocytochemical, and genotypic analyses may be simultaneously required.